BIOL 2260 Exam 4 UPDATED ACTUAL Questions and CORRECT
Answers
List and describe the six general functions of the 1. Ingestion: Introduction of solid & liquid nutrients into the oral cavity; first step in
digestive system process of digesting & absorbing nutrients
2. Motility: Voluntary & involuntary muscular contractions; mixing & moving
materials through the GI tract
3. Secretion: Process of producing & releasing fluid products facilitating digestion
(e.g., digestive enzymes, acid, bile)
4. Digestion: Breakdown of ingested food into smaller structures
- Mechanical digestion: Material physically broken down by chewing & mixing
- Chemical digestion: Involves specific enzymes to break chemical bonds; change
large complex molecules into smaller molecules
5. Absorption: Transport of digested molecules, electrolytes, vitamins, water;
move from GI tract into blood or lymph
6. Elimination: Expulsion of indigestible components that are not absorbed
Identify the six organs that make up the gastrointestinal Oral cavity & pharynx
(GI) tract Esophagus & stomach
Small intestine, large intestine, & anus
Distinguish between the digestive system, the alimentary The gastrointestinal (GI) tract is also known as the digestive tract/system or the
canal, and the gastrointestinal (GI) tract alimentary canal
List the accessory organs and structures involved in the Salivary glands, liver, pancreas
digestive process Teeth & tongue
Gallbladder
,List and describe the four tunics (layers) that make up the 1. Mucosa: Inner-lining mucous membrane
gastrointestinal wall - Consists of epithelium, lamina propria, muscularis mucosae
Epithelium: In contact with lumen contents
- Simple columnar epithelium allowing for secretion & absorption
- Portions that must withstand abrasion (i.e., esophagus)
- Lined by nonkeratinized, stratified squamous epithelium
- Underlying lamina propria: Composed of areolar tissue containing small blood
vessels & nerves; absorption occurs when substances move into these vessels
- Muscularis mucosae: Thin layer of smooth muscle deep to lamina propria;
contractions facilitate release of secretions into lumen, increase contact of
materials in lumen with the mucosa
2. Submucosa: Areolar & dense irregular connective tissue
- Blood vessels, lymph vessels, nerves
- Submucosal (Meissner's) plexus: Nerves & ganglia innervating smooth muscle &
glands
- Houses mucosa-associated lymphatic tissue (MALT): Prevents ingested microbes
from crossing GI tract wall
- Peyer's patches: Larger aggregates of lymphatic nodules in distal small intestine
3. Muscularis: Inner circular layer, outer longitudinal layer, & myenteric
(Auerbach's) plexus
- Inner circular layer of muscle: Smooth muscle cells oriented circumferentially
within GI tract; contraction constricts tube lumen
- Outer longitudinal layer: Cells oriented lengthwise along GI tract; contraction
shortens tube
- Myenteric (Auerbach's) plexus: Axons & ganglia between layers control
contractions
- Enteric nervous system: Submucosal plexus & myenteric plexus; detects changes
in tract wall & chemical makeup of lumen content; sensory & motor neurons
- Thickened at several points to form a sphincter: Closes off the lumen; controls
movement of materials into next section of GI tract
- Functions to propel contents within GI tract
- Mixing: "Backward-&-forward" motion that lacks directional movement; blends
ingested materials with secretions
- Peristalsis: Alternating contraction sequence of inner & outer layers; propels
ingested materials through tract
4. Adventitia (or serosa): Outermost tunic may be either
- Adventitia: Found outside the peritoneal cavity
- Serosa: Completely covered by visceral peritoneum; found within peritoneal
cavity
Explain the action of the muscularis tunic Motility: Mixing & propulsion
- Mixing: "Backward-&-forward" motion that lacks directional movement; blends
ingested materials with secretions
- Peristalsis: Alternating contraction sequence of inner & outer layers; propels
ingested materials through tract
Name and locate two nerve plexuses associated with the Enteric nervous system (ENS): Extends from esophagus to anus
wall of the GI tract Autonomic nervous system (ANS): Parasympathetic & sympathetic divisions
innervate smooth muscle & glands of GI tract wall
Briefly describe the general process of absorption Transport of digested molecules, electrolytes, vitamins, water; move from GI tract
into blood or lymph
, Describe the structure of the serous membranes Parietal peritoneum: Lines inside surface of abdominal wall
associated with the digestive tract Visceral peritoneum: Serous membrane reflecting over & covering the internal
organs' surface
Distinguish between intraperitoneal and retroperitoneal Intraperitoneal organs: Organs completely surrounded by visceral peritoneum
organs - Includes stomach, most of small intestine, parts of large intestine
Retroperitoneal organs: Lie directly against posterior abdominal wall
- Only anterolateral portions covered with peritoneum
- Includes most of duodenum, the pancreas, ascending & descending colon, the
rectum
Explain the function of four parts of the peritoneum Peritoneum: Supports, suspends, stabilizes intraperitoneal GI tract organs
- Blood & lymph vessels, nerves, are sandwiched between the folds
1. Greater omentum: Extends inferiorly from inferolateral stomach
- Covers most abdominal organs
- Accumulates large amounts of adipose tissue (fatty apron)
2. Lesser omentum: Connects superomedial surface of stomach & proximal end of
duodenum to the liver
3. Falciform ligament: Flat, thin crescent-shaped fold that attaches the liver to
internal surface of anterior abdominal wall
4. Mesentery proper: Fan-shaped fold of peritoneum
- Suspends most of small intestine from posterior abdominal wall
5. Mesocolon: Fold of peritoneum
- Attaches part of large intestine to posterior abdominal wall
- Several distinct sections named for portion of colon suspended
Identify the type and location of the two main receptors 1. Baroreceptors: Detect stretch or pressure in GI tract as contents moves through
of the digestive system 2. Chemoreceptors: Detect specific substances of passing contents within the
lumen
List the major hormones that regulate the processes of 1. Gastrin: From stomach
digestion 2. Secretin: From small intestine
3. Cholecystokinin: From small intestine
What is the primary difference between mechanical - Mechanical digestion: Material physically broken down by chewing & mixing
digestion and chemical digestion? - Chemical digestion: Involves specific enzymes to break chemical bonds; change
large complex molecules into smaller molecules
Describe the components of the upper gastrointestinal Oral cavity & salivary glands: Mechanical digestion begins here
tract - Saliva secreted from salivary glands in response to food
- Contains salivary amylase, enzyme initiating digestion of starch
- Mixed with ingested materials to form bolus
Pharynx: Bolus moved here, where swallowing occurs
- Mucus secreted here to facilitate swallowing
Esophagus: Bolus transported from pharynx into stomach
- Lubricated by mucus secretions
Stomach: Bolus mixed with gastric secretions by smooth muscle contractions
- Secretions produced by epithelial cells of stomach
- Chyme formed from mixing
- Duodenum also part of upper GI tract, discussed with small intestine
Answers
List and describe the six general functions of the 1. Ingestion: Introduction of solid & liquid nutrients into the oral cavity; first step in
digestive system process of digesting & absorbing nutrients
2. Motility: Voluntary & involuntary muscular contractions; mixing & moving
materials through the GI tract
3. Secretion: Process of producing & releasing fluid products facilitating digestion
(e.g., digestive enzymes, acid, bile)
4. Digestion: Breakdown of ingested food into smaller structures
- Mechanical digestion: Material physically broken down by chewing & mixing
- Chemical digestion: Involves specific enzymes to break chemical bonds; change
large complex molecules into smaller molecules
5. Absorption: Transport of digested molecules, electrolytes, vitamins, water;
move from GI tract into blood or lymph
6. Elimination: Expulsion of indigestible components that are not absorbed
Identify the six organs that make up the gastrointestinal Oral cavity & pharynx
(GI) tract Esophagus & stomach
Small intestine, large intestine, & anus
Distinguish between the digestive system, the alimentary The gastrointestinal (GI) tract is also known as the digestive tract/system or the
canal, and the gastrointestinal (GI) tract alimentary canal
List the accessory organs and structures involved in the Salivary glands, liver, pancreas
digestive process Teeth & tongue
Gallbladder
,List and describe the four tunics (layers) that make up the 1. Mucosa: Inner-lining mucous membrane
gastrointestinal wall - Consists of epithelium, lamina propria, muscularis mucosae
Epithelium: In contact with lumen contents
- Simple columnar epithelium allowing for secretion & absorption
- Portions that must withstand abrasion (i.e., esophagus)
- Lined by nonkeratinized, stratified squamous epithelium
- Underlying lamina propria: Composed of areolar tissue containing small blood
vessels & nerves; absorption occurs when substances move into these vessels
- Muscularis mucosae: Thin layer of smooth muscle deep to lamina propria;
contractions facilitate release of secretions into lumen, increase contact of
materials in lumen with the mucosa
2. Submucosa: Areolar & dense irregular connective tissue
- Blood vessels, lymph vessels, nerves
- Submucosal (Meissner's) plexus: Nerves & ganglia innervating smooth muscle &
glands
- Houses mucosa-associated lymphatic tissue (MALT): Prevents ingested microbes
from crossing GI tract wall
- Peyer's patches: Larger aggregates of lymphatic nodules in distal small intestine
3. Muscularis: Inner circular layer, outer longitudinal layer, & myenteric
(Auerbach's) plexus
- Inner circular layer of muscle: Smooth muscle cells oriented circumferentially
within GI tract; contraction constricts tube lumen
- Outer longitudinal layer: Cells oriented lengthwise along GI tract; contraction
shortens tube
- Myenteric (Auerbach's) plexus: Axons & ganglia between layers control
contractions
- Enteric nervous system: Submucosal plexus & myenteric plexus; detects changes
in tract wall & chemical makeup of lumen content; sensory & motor neurons
- Thickened at several points to form a sphincter: Closes off the lumen; controls
movement of materials into next section of GI tract
- Functions to propel contents within GI tract
- Mixing: "Backward-&-forward" motion that lacks directional movement; blends
ingested materials with secretions
- Peristalsis: Alternating contraction sequence of inner & outer layers; propels
ingested materials through tract
4. Adventitia (or serosa): Outermost tunic may be either
- Adventitia: Found outside the peritoneal cavity
- Serosa: Completely covered by visceral peritoneum; found within peritoneal
cavity
Explain the action of the muscularis tunic Motility: Mixing & propulsion
- Mixing: "Backward-&-forward" motion that lacks directional movement; blends
ingested materials with secretions
- Peristalsis: Alternating contraction sequence of inner & outer layers; propels
ingested materials through tract
Name and locate two nerve plexuses associated with the Enteric nervous system (ENS): Extends from esophagus to anus
wall of the GI tract Autonomic nervous system (ANS): Parasympathetic & sympathetic divisions
innervate smooth muscle & glands of GI tract wall
Briefly describe the general process of absorption Transport of digested molecules, electrolytes, vitamins, water; move from GI tract
into blood or lymph
, Describe the structure of the serous membranes Parietal peritoneum: Lines inside surface of abdominal wall
associated with the digestive tract Visceral peritoneum: Serous membrane reflecting over & covering the internal
organs' surface
Distinguish between intraperitoneal and retroperitoneal Intraperitoneal organs: Organs completely surrounded by visceral peritoneum
organs - Includes stomach, most of small intestine, parts of large intestine
Retroperitoneal organs: Lie directly against posterior abdominal wall
- Only anterolateral portions covered with peritoneum
- Includes most of duodenum, the pancreas, ascending & descending colon, the
rectum
Explain the function of four parts of the peritoneum Peritoneum: Supports, suspends, stabilizes intraperitoneal GI tract organs
- Blood & lymph vessels, nerves, are sandwiched between the folds
1. Greater omentum: Extends inferiorly from inferolateral stomach
- Covers most abdominal organs
- Accumulates large amounts of adipose tissue (fatty apron)
2. Lesser omentum: Connects superomedial surface of stomach & proximal end of
duodenum to the liver
3. Falciform ligament: Flat, thin crescent-shaped fold that attaches the liver to
internal surface of anterior abdominal wall
4. Mesentery proper: Fan-shaped fold of peritoneum
- Suspends most of small intestine from posterior abdominal wall
5. Mesocolon: Fold of peritoneum
- Attaches part of large intestine to posterior abdominal wall
- Several distinct sections named for portion of colon suspended
Identify the type and location of the two main receptors 1. Baroreceptors: Detect stretch or pressure in GI tract as contents moves through
of the digestive system 2. Chemoreceptors: Detect specific substances of passing contents within the
lumen
List the major hormones that regulate the processes of 1. Gastrin: From stomach
digestion 2. Secretin: From small intestine
3. Cholecystokinin: From small intestine
What is the primary difference between mechanical - Mechanical digestion: Material physically broken down by chewing & mixing
digestion and chemical digestion? - Chemical digestion: Involves specific enzymes to break chemical bonds; change
large complex molecules into smaller molecules
Describe the components of the upper gastrointestinal Oral cavity & salivary glands: Mechanical digestion begins here
tract - Saliva secreted from salivary glands in response to food
- Contains salivary amylase, enzyme initiating digestion of starch
- Mixed with ingested materials to form bolus
Pharynx: Bolus moved here, where swallowing occurs
- Mucus secreted here to facilitate swallowing
Esophagus: Bolus transported from pharynx into stomach
- Lubricated by mucus secretions
Stomach: Bolus mixed with gastric secretions by smooth muscle contractions
- Secretions produced by epithelial cells of stomach
- Chyme formed from mixing
- Duodenum also part of upper GI tract, discussed with small intestine
